Power transistors commonly employed in automotive and industrial electronics require a low on-state resistance (Ron), while securing a high voltage blocking capability. For example, a MOS (“metal oxide semiconductor”) power transistor should be capable, depending upon application requirements to block drain to source voltages Vds of some tens to some hundreds or thousands volts of volts. MOS power transistors typically conduct very large currents which may be up to some hundreds of Amperes at typical gate-source voltages of about 2 to 20 V.
Lateral power devices, in which current flow mainly takes place parallel to a first main surface of a semiconductor substrate, are useful for integrated circuits in which further components, such as switches, bridges and control circuits are integrated.
So-called TEDFETs (“Trench Extended Drain Field Effect Transistors”) have been developed in order to accomplish a power device having an improved trade-off between low on-state resistance and high voltage blocking capability. TEDFETs specifically rely on the effect of accumulation in the drift region of a field effect transistor (FET).
In view of the above, there is a need for a lateral MOS power transistor which can be manufactured by a simple and cheap process.